Terrie Tafoya
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PEDs, Supplements, And PCT Used, Dosage, And Duration
Introduction
Performance‑enhancing drugs (PEDs) are widely used by athletes, bodybuilders, and fitness enthusiasts to accelerate muscle growth, increase strength, and improve recovery times. While PEDs can produce impressive results, they also carry significant health risks and legal implications. Understanding the proper use of PEDs—including recommended supplements, dosage limits, post‑cycle therapy (PCT), and cycle length—is essential for anyone considering these substances.
PEDs Overview
The most commonly used anabolic agents include testosterone esters, nandrolone decanoate, trenbolone acetate, stanozolol, and selective androgen receptor modulators (SARMs) such as ostarine. Each compound differs in potency, half‑life, side‑effect profile, and required dosage. For example:
Testosterone cypionate: 200–500 mg/week
Nandrolone decanoate: 50–100 mg every 2–3 weeks
Trenbolone acetate: 30–60 mg/2 days
The dosing schedule must align with the drug’s pharmacokinetics to maintain steady‑state plasma concentrations and minimize peaks that trigger side effects.
3. Timing of Blood Draw Relative to Dosing
Blood draws should be performed at a time when the plasma concentration reflects steady‑state rather than a transient peak or trough. Two common strategies exist:
Strategy When to Sample Rationale
Early morning after overnight fast (pre‑dose) ~8 am, before next dose Captures trough level; useful for drugs with high inter‑individual variability at peak
Mid‑interval sampling 4–6 h post‑dose (for half‑life 3–5 h) Approximate steady‑state concentration (neither peak nor trough)
For a drug with a half‑life of ~3 h and dosing every 12 h, sampling at 6 h after the dose typically yields a concentration that approximates the average exposure over the dosing interval.
2.3 Pharmacokinetic Parameters for Dosing Regimen
Parameter Description
Cmax Peak plasma concentration (after dosing).
Cmin Trough concentration before next dose.
AUC0–τ Area under the concentration‑time curve over one dosing interval τ.
Half‑life (t½) Time for plasma concentration to halve.
Clearance (CL) Volume of plasma cleared per unit time.
Volume of distribution (Vd) Apparent volume in which drug is distributed.
These parameters inform how often a dose should be given and whether a steady‑state will be achieved safely.
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2. Steady‑State Pharmacokinetics
2.1 What Is "Steady State"?
After repeated dosing, the amount of drug entering the body equals the amount being eliminated during each interval. At this point the plasma concentration fluctuates around a predictable peak and trough but does not increase or decrease over time.
2.2 How Many Doses Are Needed to Reach Steady State?
For most drugs, steady state is reached after about 4–5 half‑lives of the drug (i.e., when the remaining unmetabolized drug in the body has decayed to ~1 % of its original amount). This is because each dose adds a fraction of the previous dose’s concentration; after 4–5 half‑lives, additional doses add only a negligible increment.
Drug Half‑life (hrs) Time to Steady State
Aspirin <1 hr ~4–5 hrs
Metformin 4 hrs ~20 hrs
Caffeine 3–5 hrs ~15–25 hrs
2.2 How Many Doses to Reach a Target Concentration?
Assuming a single dose is administered every \(T\) hours, the concentration just before each new dose (\(C_pre\)) follows:
[
C_pre(n) = C_0 \cdot e^-k(n-1)T + \fracDV_d\sum_i=0^n-2e^-k(i+1)T
]
where:
\(C_0\): concentration immediately after the first dose,
\(k = \ln 2 / t_{½}\),
\(D/V_d\): concentration increment per dose.
For large \(n\), \(C_pre(n)\) approaches a steady‑state value:
[
C_\textss = \fracDV_d \cdot \frac11 - e^-kT
]
The number of doses required to reach within \(\epsilon\%\) of the steady state can be estimated by solving:
[
e^-nkT \leq \epsilon
\;\Rightarrow\;
n \geq \frac\ln \epsilon-kT
]
Applying these formulas with the specific parameters (dose, dose interval \(T\), clearance rate) yields the precise count of administrations necessary to achieve a given target concentration or percentage of maximum effect.
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Summary
To determine how many times an animal must be treated for the drug’s effect to reach a desired level:
Model drug kinetics using first‑order elimination (or a more detailed PK model if needed).
Calculate the steady‑state or cumulative concentration after repeated dosing.
Translate that concentration into pharmacodynamic response via an appropriate dose–response curve.
Use the equations above to solve for the number of doses required, given the target effect.
This approach allows you to predict accurately how many administrations are needed to achieve a specific therapeutic outcome in the animal.
