SteroidPlotter is the leading steroid cycle planner on the Web. Plot graphs and calculate levels for Anabolic Steroids, TRT & Peptides based on dosage & half-life.

Use our steroid plotter to plan and plot your cycle or protocol and share it with friends. You can start from scratch or get started by using one of our preset examples in the list below. You can include anabolic steroids, peptides, and pharmaceuticals.

Example Protocols

Click to view the protocol with graph.

Plot Your Protocol

NOTE: We aim to make our calculator as useful as possible based on publicly available studies and data. However, there are significant limitations, assumptions are made, and a simplified pharmacokinetic model is used. The half-lives and pharmacokinetic variables used are estimates and will differ between individuals. This tool is for entertainment only and should not be used to make medical decisions. Always consult a healthcare professional before altering any medication regimen. This calculator and its content are not medical advice. Use at your own risk.


  • Where possible, we obtain the elimination half-life (t1/2), peak concentration (Cmax), time to peak (Tmax), and bioavailability (F(%)) of included compounds from peer-reviewed scientific studies.
  • Sometimes, certain pharmacokinetic values are less easy to ascertain. In these cases, we have to make assumptions to estimate these values, which will not accurately reflect the behavior of these compounds in real-world scenarios.
  • Pharmacokinetic data and studies/sources used for compounds used in the plotter application are included below.
  • Please visit our FAQs page for the most frequently asked questions we receive about the SteroidPlotter website & application.

Pharmacokinetics & Sources:

We are currently maintaining a Google Sheet listing current pharmacokinetics and sources. This sheet is a work in progress and will be ported to the website once completed.

If you have any feedback or suggestions or want to see a new compound added, please do not hesitate to contact us in our Telegram group.

142 thoughts on “”

  1. Hello, thanks for such an amazing calculator!

    I’m a little confused about Masteron propionate vs enanthate.
    Comparing ED dosing of Test prop vs enanthate shows a higher consideration of test prop. But comparing ED dosing of Mast prop vs enanthate, shows a much higher consentration of enanthate. Is this accurate, even though propionate is lighter than enanthate, thus more Mast per mg with prop?



    Appreciate your insight!

    • Hey and thanks for the comment. Unfortunately there is a bit of mix and match between the compounds/esters and algorithms used to calculate levels based on available data.

      For now, we look for studies using the specific compound and ester to get half-life and pharmacokinetic data. If additional data is available, we use a more complex and accurate model, but this isn’t always the case so we fall back to a simplified model in some cases.

      We may simplify the approach at some point, but it’s not currently clear if different compounds behave exactly the same when attached to the same ester and I suspect this is not the case.

      You can view the list of studies used and the associated pharmacokinetic data on our Google Sheet which is linked to from the homepage. Hope this helps.

  2. Hello!! Thanks for the excellent steroid calculator!!
    How can the calculator implement the possibility of switching from nandrolone phenylpropionate to decanoate, so that the background is even?
    The same with testosterone undecanoate and enanthate. I take enanthate Wednesday evening /Sunday morning (every 3.5 days). I have to go on vacation for 2 weeks, and there is no way to take an enanthate with me. How much do I need to take undecanoate and calmly go on vacation, and upon arrival, how do I return to my enanthate dosages?
    Please add the option to choose the reception only by days of the week!!
    Thank you again!!

    • You can quite easily switch between compounds in the calculator. Simply stop one for n weeks and start the other. You can overlap if required. To dose on specific days you can, for now, simply use the offset function to shuffle a weekly dose to a specific day. Hope that helps.

  3. New calc looks good! It would be awesome if we could adjust the concentration scale based on a known test result. This takes into account how different people react to different dosages. For example, lest say you are already on a cycle of Test Cyp 100mg, once every 7 days. The plotter shows a trough of approx 700ng/ml. But when you get your bloodwork done, you find that your trough is closer to 500ng/ml. It would be cool to be able to choose an offset for that concentration scale by 200ng/ml to have it align with your known result, so that you could more accurately project dosage changes and likely outcomes. Of course we can do this math by hand, but would be a cool feature for the plotter.

    • Nice idea. We will look into adding a multiplier option so that users can push the results up or down by a specific percentage.

  4. You’ve broken a calc that used to actually work for models that have completely wild assumptions that won’t match 99% of real life case scenarios. The switch from mg/day to actual blood concentration is already stupid by itself, but you even went back to a SEVEN DAY half life for testosterone enanthate when the previous version had it right at 4.5, basing your results on a SUBCUTANEOUS INJECTION STUDY instead of the old “Comparative pharmacokinetics of testosterone esters” with actual IM values. And then you have tren E at 11 for… reasons….

    Can you at least offer a link to the old calc somewhere? This is useless.

    • Sources to all studies used are in the Google Sheet linked to from the homepage. No, they won’t reflect real world scenarios for everyone and we do not suggest that they do.
      The old version assumes instant release of the compound into the blood. This is far, far more inaccurate than the models we are using now, but suit yourself.

      The old site is literally linked as “Old Site” in the footer or easily found in Google.

  5. If i enter 0mg of Testosterone Cypionate every 4 days it draws a curve going from 0 to 300ng/dL in a few weeks. I wish it worked that way, but why does SteroidPlotter do this?

    • Hey, thanks for the heads up.

      This looks like a bug with our linear regression model at very low doses. Currently this model is only live for Test E and Test C.

      It should be more accurate at realistic doses from the lower end of TRT and up but we will need to look at modifying for very low doses.

  6. Hi,
    Love the app. Thx
    How can i download a planned cycle into excel showing the injection scheduled?
    Downloading the the graph into excel doesn’t do that. The graph excel download also defaults the dates 1970/01/01 00:00:00
    Secondly, when you add a compound later in the cycle then the graph excel download seems to add the compound from line 1 (with the aforementioned default date)

    • We have plans to add the ability to export injection schedules, so keep an eye out for that.

      Downloading the data should work fine, you probably need to set the correct data format in Excel in the date column. If you open the csv file in a text editor you will see the correct dates.

      Any compound added later in the cycle will show from the first line in the CSV export but will show as 0 until the date at which it starts being used.

  7. I think there is an issue with test D, when I plotted switching from test C to D the blood levels almost doubled. It looks correct on the old site though. Thanks for all the work you put into this.

    • Hi there, Test C uses our advanced model and includes linear regression whereas Test D uses a simplified model. You will likely see more accurate results with the model used for Test C, but unfortunately we don’t have the data we need to utilize this model for Test D.

  8. Be nice if you added in Sustanon 250 as it is popular enough I believe to warrant it and entering the different esters manually is a PITA. Thanks.

    • Thanks for the comments and support. There have been many requests for Sust 250 now – we will look to get this added soon.

  9. As some one just starting out.. how do you factor in natural levels? Wouldn’t there be a point where exogenous and endogenous levels kind of mix before endogenous production shuts down?

    • The tool does not account for natural levels. The results seen in the tool are estimates for users that are fully shut down.

    • When using anabolic steroids, their natural production will be reduced to zero after a week, a maximum of one and a half. Those crumbs that remain will no longer affect the overall picture. Moreover, all these calculations are theoretical conventions and AAS metabolism may vary from person to person.

      • This tool cant estimate or guess your total level including your endogenous testosterone levels though, just an FYI

    • Depending on the hormone/sarm your body’s shutdown time will vary.
      But to directly answer, yes your bodys natural levels will be added to whatever exogenous hormone you take.
      Also I believe it takes longer to suppress when the hormone you take doesnt aromatize, for example testosterone aromatizes to e2, but Proviron doesnt so shutdown might not happen or will be less.
      Also longer esters like Cypionate take longer to build up in your blood than as ester like propionate

    • We have Tren E as an 11 day half life and Tren A as 1.5 day so yes, Tren E will result in far higher steady state levels.

      • I thought all Enanthate esters had a 5-ish day half life. Interesting. So there’s no reason at all to pick Tren A when you can get much more for much less money.

        • Well there is, Tren A is much better for first contact with Tren since if you feel unwell while using it, just cut it and within a week it’s all gone from your system. Hit it with Test P or Sustanon and you’re “golden”.

        • Obviously if you are thinking about economics you must be pretty new to this. The differences between Tren A and E are huge and I suggest you go out and learn why Tren A is the compound of choice for the vast majority of people , knowledgeable people, using Tren. Not my, or our , job to spoon feed you. Put in the work!

      • Tren E half life should be around 5 days, and the HEX ester around 11 days. Hex is the longest ester of Tren available. Looking at the results of the graph I just made, I think the two are mixed up… just FYI

          • That source is just a study on the crystal structure of the molecule. I don’t have full access though so I’ve requested it via researchgate from the authors but still awaiting a reply. Are you able to provide an extract of the bit that actually says it’s 11 days half-life?

            Only it would seem odd for the same ester to have a different half-life jsut because the attached molecule is different unless the bonding arrangement is somehow different (test e is 4.5 days for example).

          • “while trenbolone enanthate has the longest duration of action, with a half-life of 11 days”

            It is in the extract. No citation though.

          • Author’s reply screenshotted below, happy to share full details privately, just not via imgur.

            I think they probably just took it incorrectly as common knowledge. They’re the only source I see cited for it after they publishedand filtering google results prior to 2020 just has people assuming 7-10 days as the ‘common knowledge’ enanthate ester half-life at the time.

            Personally I’m inclined to assume the same as other enenthates, ideally accounting for typically used carrier oils? Not sure tbh

          • That’s great. Thanks for going out your way to get that confirmed.

            Do you happen to know of any decent sources to use for references here so we can get these values updated? We can consider using pharmacokinetic data for different compounds with the same ester.

            Feel free to hop on the Telegram group to discuss if that’s any easier.

      • This is misleading because tren e wont result in higher steady state levels, the ester just makes it take longer to release the active non esterfied trenbolone. Tren e is not 5x more powerful than tren a its just more slowly released, the tren doesnt stay in your blood for longer. 500 Tren A injected frequently is slightly more powerful than 500mg Tren E because theres more actual trenbolone in the Oil however the calcuator is showing Tren E to have ridiculously high blood levels and its not true

        • Steady state is typically far higher for drugs with longer half lives at the same mg for mg dosage and frequency.

          Have a look into the steady state formulas which account for clearance and volume of distribution.

  10. How can you change the graph to start at a specific time of day? E.g, I inject at 5pm but this graph only alternates between 12pm and 12am.


  11. Is this broken now? You used to be able to plot past your cycle length to see post cycle blood levels..:.not sure what happened.

    • What do you mean? Can you share a link to your cycle? If your cycle is 20 weeks then simply set the length to 28 weeks then stop the compounds after 20. If you want to see beyond the weeks you have specified then simply add more.

  12. What a fantastic tool!

    Is there a way to export all of the doses to a calendar of the example protocols? It doesn’t have to be to any of my computer/personal calendars, but to a calendar in a PDF or some other form, for reference and schedule to follow? Let me know if I’m not being clear.

    • Thanks, Ethan! That’s a great idea. We don’t currently have a calendar export feature but will keep it in mind for future updates.

      • Thank you for your reply!

        Yeah, think about it, a person would have a far more organized way to remember doses and follow a schedule (at least for my OCD self who likes to be overly certain about things). Then all of the math would be consistently correct instead of a end-user wondering if they did a calculation error.

        I really mean it when I say that I appreciate this tool, along with the GLP-1 tool. I’ve been sharing it with all of my GLP-1 and lifting friends. I probably share them 5-10 times a week. Anyway, thank you for the tools!

  13. Do i have to add the mg from the total (test+ester) or the real test mg in the drug?
    Like Each 1ml ampoule contains 250mg Testosterone Enantate (the equivalent of about 180 mg testosterone), so i add 250mg or 180mg for the calcs?

    • It’s a little tricky to combine them as a single compound due to the way the application is built. What percentage of each ester is your Sustanon? We could perhaps add a TRT template for it but it would require manual adjustment for dosage, frequency, etc.

  14. Fellas, your T1/2’s for Te and Tc are off for app 2 days and why the heck do you think Tc has a Tmax of 4.5 days!? Te also doesn’t have a Tmax of 1.3 days. Those are some odd numbers, and I do know from which studies you got them, you should conduct a more broader look at studies. Also, peak for Te/Tc is going to be mostly somewhere between 10 to 20h; dependent on injection depth, which muscle was injected, bolus size and carrier oil.

    Most anybody who’s been either on trt for a long time or is a bodybuilder/coach and knows his personal/clients pk’s knows – T1/2 for Te/ Tc is closer to 5 days, maybe less. You guys are either complete newb’s to the game or are some nerds reading studies on the net, lacking the industry know how – which includes conducting and interpreting studies.

    This site has great potential, but you’ve got some glaring issues, like the aforementioned pk parameters, that you need to fix and you’ll be golden. As it stands now, you’re somewhat of a hub for misinformation for newb’s then anything else, and industry vet’s aren’t using and recommending your site at all.

    • All of the studies we use for pharmacokinetic data are public in the Google sheet.

      Can you please provide links to these other studies you’ve seen in your broader search? Happy to adjust data where there are reasonably well conducted trials. Also please feel free to include any specific examples where studies have been misinterpreted.

      As for “anyone who’s been on TRT for a long time knowing better”, we get plenty of messages here, via the contact form, and on telegram about how accurate the new models are in relation to blood results, in many instances. Obviously not for everyone, but being a non-nerd expert I suppose you are aware of the individual variation and large confidence intervals seen in the studies.

      We’re not going to update data based on your anecdotes, but if you can actually provide some substance, rather than veiled insults then do so and we’ll take a look.

      • Lol, great response. One only has to notice the poor grammar, and completely imprecise numbers being thrown around, to realize that this is someone well versed in “Bro” Science but lacking much of anything else.
        Most anybody who has the intention to, or knows how to, refute data in a situation like this knows you need to come to the table with peer reviewed citations in order to make your point otherwise you are simply another armchair internet expert blowing smoke up people’s behinds, lol!

        Keep up the solid work guys.

  15. I would amend the pharmacokinetic profile used here for the acetate and propionate esters (of all AAS). Studies seem to show an approx. 0.8 day half life for Testosterone Propionate, and from my own testing as well as what I’ve seen many other users on the excelmale forums post, it seems that the propionate ester typically results in serum Total T levels being <1/2 of Cmax 24 hour later. Given differences in muscle type, carrier oils and other inter-individual differences, it also seems that the T tmax for this ester seems to occur anywhere between 1-6h post injection.

    A lot of the older studies looking at the pharmacokinetics of Testosterone esters seem to be incorrect and we're only starting to notice this now with increased numbers of users getting tested.

    • We can’t really use anecdotal data. The plotter is never going to give accurate levels for everyone as there is lots of individual variation seen in the studies.

      However, we may eventually add the ability to add custom compounds/data, where you can input your own metrics.

      • Especially anecdotal from the excelmale forum lol…not the most knowledgeable lot when it comes to much of anything. Nelson is a nice guy who had a great idea but the forum seems to attract some awfully stupid people lol!

  16. Hi, I noticed that Tren Acetate & Enanthate at the same weekly dose seems to showcase a drastic concentration difference. Is the plotter not taking into consideration the bioavailabilty for Trenbolone?

    Testosterone Propionante & Enanthate (similar ester lengths for comparison) does not produce the same odd concentration difference.

  17. Hello, does the chart database takes in account the conversion of testosterone in DHT and Estradiol in the body to conclude about the testosterone concentration (ng/dl) after, for instance, the testosterone enanthate shots?

  18. How reliable are these values with Enanthate at low dosages? I am on high-dose HCG with a resting T of ~450 looking to bump to 700 via Enanthate. By this chart, 20 MG Enanthate (10mg 2x per week) is enough to roughly accomplish that?

    • For Test E, we used the pharmacokinetics from this study:
      Then used linear regression to fit to the data here:

      As for reliability, it will be less accurate for doses well outside of those used in the study but it’s unlikely to match your unique circumstances exactly, regardless, as there is lots of individual variation in resulting blood levels.

      It could also be complicated further by the introduction of exogenous testosterone lowering your natural production. I assume this happens to some extent, even with HCG, but have no direct experience. Best thing to do in your case could be to try out a protocol and then get bloods after 6 weeks once any endogenous shutdown may have happened.

  19. Mike here. Just wanted to ask did you get my answer to test enanthate/cypionate question? I used reply button. Also writed about other things.

    • Hi Mike. I’m on vacation for another week or so, so will a little while before I can reply to contact form messages and comments. Will get back to you later though.

  20. 250mg sustanon (iscaproate) twice a week yields serum levels almost double the same dose and schedule of test enanthate.
    How is this possible?

    • Isocaproate uses a simplified model due to lack of pharmacokinetic data available for that ester so it will be less accurate.

      That said, I’ve adjusted it’s multiplier so it will more closely match Test E (actually slightly lower blood levels due to the smaller half life).

    • What do you mean exactly? Tapering PCT meds down gradually? If you have an example we’d be happy to add it.

      • Tapering is a method in which steroid users reduce the dose by adjusting the endogenous hormone levels according to the steroid half-life without PCT, but in fact, I do not have an exact example.

    • Hey mate so I’m taking Test E 300mg 1ml per week for 10 weeks I just wanted to know are you saying it’s still not peaked yet ? This is my second cycle but this time I’m doing it properly as In sticking to the same amount for 10 straight weeks with a pct 2 weeks before finishing

  21. Did something recently get updated? I swear I am getting much lower concentration values on test enan than I was a few days go…

  22. is it valid to use 100mg masteron propionate with 150mg test enanthate 2x week? I’m using this now. I’m from Brazil so here we don’t have much access to the masteron enanthate wich would be the ideal. any suggestion ?

  23. In the dosage of testogel in mg, is the reference to total mg of gel or to the bioavailable ones? Since the bioavailability of the gel is around 10%. So a 50mg sachet would have a real 5mg.

  24. If propionate is taken daily, how long after the dose will it reach peak concentration? Would taking prop before bed at 10pm result in a peak concentration around 6-8am? I’m considering using prop for trt and attempting to replicate natural rhythm.

        • The pharmacokinetics of test prop we are using are as follows:

          half life = 1.0375 days
          Tmax = 1.0625 days

          The maximum plasma testosterone-19-d3 levels (15.0 ng/ml for subject 1 and 11.5 ng/ml for subject 2) occurred between 24 and 27 h.

          The full text of this paper has elimination half life listed as 26.7 hours in one subject and 23.1 for the other.

          Given the above, you’d expect relatively stable levels with a daily dose. If you’re looking for more variation between peak and trough consider EOD dosing.

          • Yes the half life has always been considered to be little more than 24h, so testosterone levels should vary, the old steroidplotter gave a totally different graph for propionate, the milligram release was actually cut in half from peak to through on a daily schedule.

          • The old site does not account for other pharmacokinetic variables so is considerably less realistic. It simply assumed instant release of all compounds which is almost never the case.
            Tmax is included in the new version which is the amount of time it takes for levels to reach Cmax (peak levels).

            Tmax is around 1 day, as is elimination half life. Half life starts after Tmax so you’ve got 2 days from dosing to hit peak then half. I realise this is not what people are familiar with seeing on the various plotter sites but it is far more accurate and based on actual scientific studies looking at blood levels after dosing.

          • I am confused. How can half-life (the time it takes to be at 50% of peak) be shorter the time to C-Max?

      • Great work!! This is something I have been missing for years. I have tried to calculate myself what blood concentration would be with a certain release rate. Mostly using my own laboratory results. A certain dose leading to certain blood concentration. So tried to calculate from there what amount of release would lead to what amount in blood.

        Testosterone enanthate and cypionate are way too different. Cypionate Tmax time is way too long. And Cmax should be equal to enanthate. Their pharmacokinetics are nearly identical. See Comparative pharmacokinetics of testosterone esters.

        • Thanks for the comment. The full text of the study you’ve provided doesn’t show an actual Tmax for cypionate. Do you know of any studies which include the actual pharmacokinetic data for cyp which more closely matches Test E, as seen in this study?

          • Unofortunately I do not know any studies that show numerical data of cypionate Tmax. But there is blood lab result data that show cypionate is very close to enanthate.

            For sidenote:
            Are you familiar that carrier oil can have big effect to half life? Example undecanoate in castoe oil half life 33,9 days, and in tea seed oil 20,9 days.

          • Quote from “comparative pharmacokinetics of testosterone esters”

            Because testosterone cypionate, testosterone cyclohexanecarboxylate and testos-
            terone enanthate had comparable suppressing effects on LH and consequently on
            endogenous testosterone secretion, it can be concluded from these studies in normal
            volunteers that all three esters with similar molecular structure possess comparable
            pharmacokinetics of exogenous testosterone serum concentrations. Testosterone
            cypionate or testosterone cyclohexanecarboxylate do not provide a more advanta-
            geous pharmacokinetic profile than testosterone enanthate. This observation is in
            agreement with a clinical study of replacement therapy with single-dose admin-
            istration of 200 mg of testosterone cypionate in 11 hypogonadal patients (Nankin

            For testosterone enanthate.
            Single-dose pharmacokinetics of testosterone enanthate after intramuscular admin-
            istration of 250 mg testosterone enanthate to seven hypogonadal patients and the
            best-fitted pharmacokinetic profile are shown in Fig. 14.6 (Nieschlag et al. 1976).
            Maximal testosterone levels in the supraphysiological range were seen shortly
            after injection (39.4 nmol/l, tmax = 10 h). Testosterone levels below the nor-
            mal range were observed following day 12 after injection. The calculated values
            were 9911 nmol ∗ h/l for AUC, 8.5 d for MRT and 4.5 d for terminal half-life
            (Table 14.2).

            And propionate:

            Single-dose pharmacokinetics of 50 mg testosterone propionate after intramuscular
            injection to seven hypogonadal patients and the best-fitted pharmacokinetic profile
            are shown in Fig. 14.4 (Nieschlag et al. 1976). Maximal testosterone levels in the
            supraphysiological range were seen shortly after injection (40.2 nmol/l, tmax =
            14 h). Testosterone levels below the normal range were observed following day 2
            (57 h) after injection. The calculated values for AUC were 1843 nmol ∗ h/l, for MRT
            1.5 d and 0.8 d for terminal half-life (Table 14.2).

            Difference between half-life and mean residence time;
            We want to use MRT. Actual time from peak blood concentration to half of it. Example peak concentration 40 nmol. 8 days later it is 20 nmol. Mean residence time 8 days.

            11.2.2 Mean residence time (MRT)
            In recent years more and more noncompartmental methods have been used
            for pharmacokinetic analysis. Twenty years ago statistical moment theory
            was introduced to pharmacokinetic analysis (Yamaoka et al. 1978). The times
            for the individual molecules to be eliminated can be described in terms of a
            statistical distribution function, i.e. the individual molecules can be elimi-
            nated just by chance within the first minutes or might still reside in the
            body weeks later. The mean residence time is a characteristic of this collec-
            tive behaviour and is the mean of the residence times of individual mole-
            cules (Cutler 1987). The mean residence time can be regarded as the statisti-
            cal moment analogy to half-life (t1/2) (Gibaldi and Perrier 1982).
            Assuming linear pharmacokinetics, the mean residence time (MRT) is
            characteristic for a special drug, independent of the administered dose. How-
            ever, mean residence time is a function of how a drug is administered. The MRT of a drug after non-instantaneous administration, e.g. intramuscular in-
            jection, will always be greater than the MRT after intravenous administration
            and can be regarded as approximately the sum of the MRT of the drug at the
            intramuscular depot and the MRT in the general circulation (Collier 1989;
            Mayer and Brazzell 1988; Yamaoka et al. 1978).

  25. why does trenbolone enanthate have such a long half-life? Is it by any chance trenbolone hexahydrobenzyl carbonate? and is it possible to add it in the future

  26. Could you please check the ester weighting and the half life of testosterone undecanoate? Speaking of Nebido (Bayer brand): Based on my blood work 88mg per week gives me blood serum levels of around 800 ng/dl. Based on your calculator it is in the low 500s:

    Professional information from Bayer indicates the half life is 53 days for instance:

    You might want to add different options for Undecenoate since pharmacodynamics differ depending on the carrier oil or the application method used (oral or injectable).

    • Hi. thanks for your comment.

      The study we used for most of the values of Test U used 750 mg TU in 3 mL of castor oil (, which I believe is the same formula as Nebido. They did not publish half life but from eyeballing the charts it looks to be about 20 days. We then found another trail which showed an average half life of 21 days (

      I’m not sure how best to handle adjustments to half life here as Bayer have published a half life different to what was seen in the trials but it looks like their Test U is basically the same as was used elsewhere. They just about provide enough in the document you provided to add as a unique compound (t1/2 = 52 days, cmax multiplier = 0.995049, tmax = 10.5 days), so we can go ahead and add it if that’s useful? The cmax and tmax are very close to the values we got from the other trials which is good.

  27. Thanks for the new planner.
    If you start Testosterone cypionate and have a slowly increasing concentration, how does the endogenous T you have/had naturally affect the concentration? Shouldn’t you be already saturated and start from a much higher level?

    • This is a great question and something we plan on improving on in the coming weeks.

      For now, the plotter does not account for endogenous testosterone and we have not yet accounted for it in our calculation of the Cmax multiplier. For example, if a study gave 100mg of Testosterone Cypionate which peaked at 1000ng/dl our Cmax multiplier would be 10ng/dl per 1mg Test Cypionate. If the study population were still producing endogenous testosterone, this obviously is not ideal and does not scale well across doses and also means our multiplier can vary based on the doses given in the trial.

      We are planning to improve this by accounting for endogenous levels in the study population, where available, or making predictions where not so. This should make levels in the plotter more accurate, assuming that users are fully shut down.

      And then there’s HCG which is another thing to consider in terms of its effect on endogenous T 😅

  28. I like the new layout, congratulations on the update.

    There seems to be a huge peak to trough difference for testosterone cypionate when compared with the old website?

    • Yes, there will be big differences/improvements for most compounds from the old version. Check our FAQs page for more info.

  29. I understand this is all based on scientific data, but some of it just doesn’t seem to pass the eye test. Incredible work here, no doubt, but I’m just slightly confused. For example:

    – In steady state, how does 10mg of Primobolan Enanthate (Injected ED) have a HIGHER peak than 40mg of Testosterone Suspension (Injected ED)?
    – 25 mg of Testosterone Propionate (ED) has a higher peak than 40mg of Testosterone Suspension (ED).

    I just don’t see how adding an ester to testosterone suspension actually makes it MORE potent / more ng/dL than without an ester.
    For example, using this plotter, if you inject 100mg of testosterone propionate ONCE, you peak out at 3,050 ng/dL. If you inject 100mg of testosterone suspension just once, you peak out at 1,520 ng/dL. Sure, the onset is quicker with suspension, but it should also have a higher peak, no?

    I know this is only based on science, and not your personal opinion, but it just seems odd to me.

    • So in your above example, primo is falling back to the less complex model as Cmax, Tmax, etc, were not available. Test Sus is using the more complex model, so out of the two, Test Sus will be the more realistic.

      That said, it has a half life of 10.5 days compared to Test Sus having a half life of 1.375 days. The compounds with a longer half life will absolutely reach a higher steady state, often at a much lower lower dose. This is simply what happens when considering the pharmacokinetics.

      A more extreme example:
      – Oral Primobolan: 0.2083 day half life
      – Testosterone Undecanoate: 21 day half life

      Now imagine taking 100mg of both compounds each day. By day 2, there is barely any primo in circulation, but almost all of the Test U is in circulation. We now add another 100mg dose, and the Test U almost doubles, whereas the oral primo is basically starting from zero. This compounds over time. In reality this is much more complex but if we think purely about half-lives then it can help understand why certain compounds build to much higher levels.

      Another example, there is often a misconception that NPP is lighter on side effects than Deca, but the reality is that it simply reaches a lower steady state on the same dose due to the pharmacokinetics:

      As for the different esters of Testosterone, they will definitely reach varying levels due to the Cmax and the Tmax. Different studies (which use different methods) are used to acquire the values we use, though, so the results from the plotter will not be highly accurate.

      • Actually, I think I may have pinpointed the issue for Testosterone Suspension. In the “Sources/Notes” section on the spreadsheet, you have the molecular weight of Testosterone Suspension listed as “412.6.” This number is the exact same molecular weight as Testosterone Cypionate, which is a heavy ester. If anything, Testosterone Suspension’s molecular weight should be nearly identical to 288.42.

        I think I see how this error occurred. Interestingly, if you Google “Testosterone Suspension molecular weight” the first result is “ts molecular formula is C27H40O3, and the molecular weight 412.61.” However, that textbox is actually pulling from an article discussing Testosterone Cypionate.

        Based on the data you have now, Testosterone Suspension (“412.6”) has a higher molecular weight than Testosterone Enanthate (“400.6”) which does not make sense.

        Beautiful work so far, just trying to help you work out the kinks! Cheers!

        • Well spotted! And really appreciate the feedback. This site will certainly rely on users like yourself letting us know what’s working as expected and what’s not otherwise it will be very difficult to get all the compounds dialed in. I’ve updated the doc. Will eventually have all the sources and figures output below the graph so it’s more obvious where we are getting data.

          Unfortunately, though, bioavailability is not utilised in the more complex model as we know the Cmax (the max blood levels based on a mg dose) so we can ignore bioavailability. I did double-check the source study and the reference values are from horses – don’t believe we could find any data on test sus in humans. We basically used a multiplier to try to get the levels to look more like they should in humans but looks like this was not a great match. I’ve adjust the multiplier so it more closely matches the prop levels after a single dose. Let me know if you think that looks more realistic or if further adjustment is needed.

  30. Really would like to see at least a toggle between ng/dl and mg released for the Y axis (or an option to view the old version.)

    • No problem. You can access it here:

      Just be careful using the old version as the release (mg/day) was a highly inaccurate way at looking at things and not reflective of what happens in reality.
      The new version uses Tmax and Cmax. Tmax being the time it takes for a dose to peak in the blood – this can be anything from a few minutes to many days. The old version of the site assumed everything was instantly released for every compound with is not realistic.

      • That is very interesting. I’ve been using that tool for over a year now as the main tool for planning my cycles (as well as stuff like front-loading during the first week.) Thank you for the continued evolution!

      • This is very interesting to me. I’ve always used the old site to calculate projections for my peaks, based off my trough labs. My recent trough for Total Test was 584 ng/DL. Using 0.16ml (32mg) Test Cyp every 3 days. For sake of example, according to the old plotter, my trough would be a release of about 6.13mg, and the very tip peak being 8.8mg. I would then divide 8.8 by 6.13, then multiply that by 584 ng/dL to get a good idea of my peak.

        Am i just doing this wildly inaccurately?

        Btw, I really appreciate the old site being up so long. It’s fantastic. Thank you

        • Unfortunately, the old site will be inaccurate, yes. The peaks and troughs are not realistic as it assumes instant release of everything you injected immediately.
          This is not realistic and there is a period of absorption until the maximum level is reached (Tmax) after which the elimination half life kicks in. Look at our Google Sheet for the data on each compound.

          The new site should be much more accurate but won’t necessarily match you levels closely. You could consider using a multiplier based on your blood tests vs the levels you see here as a rough estimate.

          Also, in the case of Testosterone, it doesn’t appear to scale linearly, i.e. 5x the dose doesn’t cause 5x the blood levels. We use linear regression to account for this.

          • Thank you so much for your reply

            “The new site should be much more accurate but won’t necessarily match you levels closely. You could consider using a multiplier based on your blood tests vs the levels you see here as a rough estimate.”

            Yes, that’s what I was planning on doing. It’s interesting though because it’s still generally thought that once a week injections of Test C lead to too much variance in T levels between day 1 and 7. Now over time, it seems to be more manageable than previously thought.

            Thank you again, I absolutely love this site.

          • Thank you for your support.

            Yes, weekly cypionate dosing is nowhere near as bad as many assume.
            Anecdotally I have heard many people do well with a slightly larger gap between trough and peak by using test prop, testosterone gels, less frequently test C or E dosing, etc.

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