TB-500 Dosage: Loading Phase, Weekly Protocol, and Where the Numbers Come From

The protocol almost everyone runs is a loading phase of 2 to 5mg subcutaneously twice weekly for four to six weeks, followed by maintenance at 2 to 5mg once weekly. That is the answer to the query, and it is worth knowing straight away that those figures come from reported community practice rather than from a human dose finding trial, because no such trial has been published for TB-500.

This page covers where those numbers originate, why the schedule is weekly rather than daily, how to scale by bodyweight, how to convert milligrams into marks on a syringe, how long a block runs, and the arithmetic mistakes that turn a sensible protocol into a wrong dose. For mechanism and evidence rather than protocol, start with the TB-500 complete guide.

Where the Numbers Come From

TB-500 is a synthetic fragment of thymosin beta-4, a protein expressed across most human cell types, and the fragment sold under the name is the short sequence containing the actin binding region. Some vendors ship full length thymosin beta-4 under the same label, which matters for dosing because the two are not the same molecule by mass.

The research behind it is overwhelmingly preclinical: animal injury models, veterinary work, and some early stage human study of wound and eye applications. None of that is a dose finding programme for the recovery use that drives search interest here, and there is no published human curve mapping milligrams per week against a repair outcome.

So the standard protocol is a convention, repeated until it looked like a standard. BPC-157 dosing sits in a similar position with one difference: it at least has rodent doses that can be scaled allometrically into a defensible starting figure. The TB-500 numbers were not derived that way.

Loading Phase and Maintenance

The loading argument is that thymosin beta-4 binds actin inside tissue, so what matters is tissue occupancy rather than what is circulating at any moment, and occupancy builds across repeated doses. On that account the first two to three weeks are spent reaching a level rather than producing an effect, which is why loading runs at roughly double the maintenance rate and why people who stop at week two conclude that nothing happened.

That is a reasonable story and not a measured one. No published human comparison has run a loaded protocol against a flat one, so treat the loading phase as a convention with a mechanism shaped rationale behind it.

Weekly Versus Split Dosing, and the Half Life Argument

With BPC-157 the frequency question is whether to split a daily dose in two. With TB-500 it runs differently: nobody proposes daily injection, and the choice is between one weekly dose and two half doses spaced across the week.

The usual justification for weekly dosing is a long half life, a claim stated more confidently than the human pharmacokinetic data supports. What can be said is that the schedule does not depend on plasma persistence the way a daily peptide does, because the proposed mechanism is binding inside tissue rather than a receptor event tracking circulating concentration. If that holds, one weekly dose and two half doses are close to equivalent once tissue levels are established, and splitting matters mainly during loading while levels are still climbing.

Practically: split during loading, single dose during maintenance. It is a smaller variable than the total, and far smaller than whether the vial contains what the label says.

mg Per Week by Bodyweight

Most quoted protocols are flat numbers, so a 60kg person and a 100kg person are told the same thing. The obvious correction is roughly 0.1mg per kilogram per week during loading, about half that for maintenance. For a 70kg adult that gives 7mg and 3.5mg, inside the conventional range rather than contradicting it.

The table below is arithmetic applied to a community figure, not a validated formula, and the number it scales is itself unvalidated. Its value is that it stops a heavier person defaulting to the bottom of the range and a lighter person to the top.

Turning Milligrams Into Syringe Units

TB-500 is dosed in milligrams and vials are labelled in milligrams, which removes the microgram confusion behind most BPC-157 errors. What replaces it is a volume problem: TB-500 doses are large enough that a careless reconstitution puts one dose past the end of the barrel.

Three steps. Concentration is vial milligrams divided by millilitres of water added. Volume per dose is the dose in milligrams divided by that concentration. Units are that volume multiplied by 100 on a standard U-100 insulin syringe.

Worked example. A 10mg vial in 2mL of bacteriostatic water gives 5mg per mL. A 2.5mg dose is 2.5 divided by 5, which is 0.5mL, and multiplied by 100 that reads as 50 units. The same vial with a 5mg dose gives 1mL, the entire 100 unit barrel in one draw.

Avoid the rows needing two draws for one dose: two draws is two chances to misread. A 10mg vial in 1mL to 2mL keeps every dose in this table inside one barrel. Technique, including how to add water without foaming the powder, is in the reconstitution guide, and any combination can be checked against the TB-500 dosage calculator.

Cycle Length

A typical block runs four to six weeks of loading, four to eight weeks of maintenance, then a break of two to four weeks. The break is a precaution, not a requirement: there is no receptor desensitisation argument of the kind that forces breaks on the growth hormone secretagogues. The reason to stop is that continuous long term use in healthy adults has not been characterised.

Judging effect before loading is complete is judging too short an interval. For slow tissue the honest assessment point is week six to eight, roughly the timescale the tendon repair page sets out for anything acting there.

Stacking With BPC-157

Most TB-500 protocols are really stack protocols. The mechanisms do not compete, which is the sensible part of the argument, and whether the combination outperforms either compound alone in humans is unstudied, which is the part usually left out. The TB-500 versus BPC-157 comparison covers which suits which situation, and the Wolverine stack page covers the pairing as it is usually run.

The friction is that the two run on different clocks and different units: BPC-157 daily in micrograms, TB-500 weekly or twice weekly in milligrams. A typical pairing is 250 to 500mcg of BPC-157 daily alongside 2 to 5mg of TB-500 weekly. Pre-blended vials remove the ability to change one without the other, a real cost for a small convenience when the two are on different phase schedules.

Where the Arithmetic Goes Wrong

• Reading a weekly figure as a per injection figure. A protocol written as 5mg per week split twice weekly means 2.5mg per injection. Read as 5mg twice weekly it is double the intended dose.
• Carrying a concentration across vial sizes. A dose that read as 50 units on the last vial will not read the same on a different strength with a different volume of water. Recalculate each time and write the concentration on the vial.
• Reading a U-40 barrel as a U-100. The same volume reads 2.5 times differently on the two scales. Check what is printed on the syringe.
• Reconstituting too thin. TB-500 doses are large enough that an over diluted vial pushes one dose past a single barrel.
• Assuming label weight is peptide weight. Lyophilised powder is typically 70 to 90 percent peptide by mass, so a real dose runs modestly below the calculated one.
• Escalating in week two. If the loading rationale holds at all, week two is before the protocol has done what it is meant to do.

Key Takeaways

• The common protocol is 2 to 5mg twice weekly for four to six weeks, then 2 to 5mg weekly
• Those figures come from reported practice, not from a published human dose finding study
• The loading phase rests on a tissue binding argument that is plausible and untested in humans
• Scaling at about 0.1mg per kilogram per week during loading is arithmetic on a community figure, not a validated rule
• Reconstitute so a full dose fits inside one U-100 barrel, usually 1mL to 2mL in a 10mg vial
• The most common error is reading a weekly total as a per injection amount
• This is research use information and none of it is medical advice

Frequently Asked Questions

What is the usual TB-500 dosage per week?

Community protocols cluster at 4 to 10mg per week during loading and 2 to 5mg per week for maintenance, given subcutaneously. The range is wide because it was assembled from reported practice rather than from a human dose finding study, and no such study has been published. Scaling at roughly 0.1mg per kilogram per week during loading stops a heavier person defaulting to the bottom of the range, but that rule is arithmetic on a community figure, not a validated formula.

Is there a TB-500 dosage per day?

TB-500 is not conventionally dosed daily. The standard schedule is one or two injections per week, which is the main practical difference from BPC-157. As a comparison only, a 5mg weekly total is about 714 micrograms per day, but nobody administers it that way and there is no evidence that splitting it further improves anything.

How long should the TB-500 loading phase last?

Four to six weeks is the figure in common use, with twice weekly injection through that period before dropping to a single weekly maintenance dose. The reasoning is that thymosin beta-4 binds actin in tissue, so tissue levels build over repeated doses rather than tracking the plasma curve. No published human study has compared a loaded protocol against an unloaded one, so this is a convention with a mechanism shaped argument behind it, not an established requirement.

What TB-500 dosage do bodybuilders use?

Reported use in training contexts sits at the upper end of the general range, commonly 5mg twice weekly through a loading block and 2.5 to 5mg weekly afterwards, usually alongside BPC-157. There is no dose response curve showing the higher figure outperforms the lower one, and no evidence that TB-500 does anything anabolic. It is used for recovery between sessions, not for adding tissue.

Is there a TB-500 dosage calculator?

Yes, and the arithmetic is simple enough to check by hand. Concentration is vial milligrams divided by millilitres of bacteriostatic water. Volume per dose is the dose in milligrams divided by that concentration. Units are that volume multiplied by 100 on a U-100 barrel. A 10mg vial in 2mL gives 5mg per mL, so a 2.5mg dose is 0.5mL, which reads as 50 units.