Steroid, Peptide & Amine Hormones: What Athletes Need to Know

Hormones are your body's chemical messengers. They travel through the bloodstream, carrying instructions that tell different organs and tissues what to do.

For athletes, hormones influence almost everything—from energy levels and metabolism to recovery, muscle growth, sleep and performance.

Your endocrine system is constantly responding to your environment. Training, nutrition, sleep, stress and recovery all influence how hormones are produced and how effectively they work.

Although there are many different hormones, they fall into three main groups:

  • Steroid hormones

  • Peptide hormones

  • Amine hormones

Understanding these hormones helps explain why fuelling and recovery are not optional extras—they are essential parts of athletic performance.

Steroid Hormones

Made from: Cholesterol

Steroid hormones are fat-soluble, meaning they can pass through cell membranes and bind to receptors inside cells. They influence gene activity, which means their effects can be slower to appear but often last longer.

For athletes, steroid hormones help regulate:

  • Muscle growth and repair

  • Recovery from training

  • Bone health

  • Stress responses

  • Reproductive health

Examples

Testosterone

Testosterone supports:

  • Muscle protein synthesis

  • Strength development

  • Recovery

  • Bone health

  • Red blood cell production

Although often associated with male athletes, testosterone is important for all athletes.

Oestrogen

Oestrogen plays an important role in:

  • Bone strength

  • Connective tissue health

  • Muscle repair

  • Menstrual health

  • Cardiovascular health

Low oestrogen levels can affect bone health and increase injury risk.

Progesterone

Progesterone works alongside oestrogen and influences:

  • Menstrual cycle regulation

  • Body temperature

  • Recovery processes

Cortisol

Cortisol is often called the “stress hormone.”

It helps the body respond to physical demands by:

  • Releasing stored energy

  • Supporting exercise demands

  • Helping regulate inflammation

Cortisol is not a bad hormone—athletes need it. Problems occur when stress remains high for long periods without enough recovery, which can negatively affect immunity, recovery and performance.

Peptide Hormones

Made from: Amino acids (proteins)

Peptide hormones are made from chains of amino acids. Unlike steroid hormones, they cannot pass directly through cell membranes, so they bind to receptors on the outside of cells and trigger responses inside.

They play a major role in:

  • Energy regulation

  • Recovery

  • Tissue repair

  • Growth

  • Hydration

Examples

Insulin

Insulin helps move glucose from the bloodstream into cells.

For athletes, insulin supports:

  • Muscle glycogen replenishment

  • Carbohydrate storage

  • Recovery after exercise

After training, consuming carbohydrate helps restore glycogen stores so you are ready for your next session.

Glucagon

Glucagon works alongside insulin.

When blood glucose levels drop, glucagon helps release stored glucose to maintain energy availability.

Growth Hormone (GH)

Growth hormone supports:

  • Tissue repair

  • Muscle recovery

  • Growth and adaptation

Much of growth hormone release occurs during deep sleep, highlighting why recovery matters.

Antidiuretic Hormone (ADH)

ADH helps regulate fluid balance by controlling how much water the kidneys retain.

This is important for athletes because hydration affects:

  • Performance

  • Blood volume

  • Temperature regulation

Amine Hormones

Made from: Single amino acids, usually tyrosine or tryptophan

Amine hormones are unique because some act more like peptide hormones, while others behave more like steroid hormones.

They are involved in rapid responses to exercise as well as long-term metabolic regulation.

Examples

Adrenaline (Epinephrine)

Adrenaline prepares your body for action.

During exercise it increases:

  • Heart rate

  • Blood flow to muscles

  • Energy release from carbohydrate stores

  • Alertness and focus

This is part of your body's natural “fight or flight” response.

Noradrenaline

Noradrenaline works alongside adrenaline to support:

  • Focus

  • Blood pressure regulation

  • Exercise response

Thyroid Hormones (T3 and T4)

Thyroid hormones regulate metabolic rate—how quickly your body uses energy.

They influence:

  • Energy levels

  • Temperature regulation

  • Growth

  • Recovery

When energy availability is too low, thyroid activity can decrease as the body attempts to conserve energy.

Why Do These Hormones Matter for Athletes?

Hormones do not work independently. They communicate constantly to help your body respond to training.

When you are eating enough, sleeping well and recovering properly, hormones help you:

  • Train harder

  • Recover faster

  • Build muscle

  • Maintain strong bones

  • Regulate energy

  • Adapt to training

Training is the stimulus—but hormones help control the response.

What Happens When Athletes Underfuel?

Your body is designed to protect you.

When energy intake is consistently too low compared with training demands, the body begins to prioritise essential functions and reduce processes that require more energy.

This can affect hormones involved in:

  • Reproduction

  • Metabolism

  • Recovery

  • Bone health

Low energy availability (LEA) can contribute to changes in hormones such as:

  • Reduced reproductive hormones

  • Reduced thyroid activity

  • Altered cortisol responses

  • Reduced testosterone

Over time, these changes can contribute to:

  • Fatigue

  • Reduced performance

  • Increased injury risk

  • Poor recovery

  • Menstrual disturbances

  • Impaired bone health

These hormonal disruptions are key features of Relative Energy Deficiency in Sport (REDs).

How Athletes Can Support Healthy Hormone Function

1. Eat Enough Energy

The foundation of healthy hormones is enough energy availability.

Your body needs energy for:

  • Training

  • Recovery

  • Hormone production

  • Bone maintenance

  • Immune function

  • Everyday life

More training means your fuel needs increase.

2. Prioritise Carbohydrates

Carbohydrates are essential fuel for high-intensity exercise.

They support:

  • Muscle glycogen

  • Training quality

  • Recovery

  • Thyroid function

  • Stress regulation

The harder you train, the more important carbohydrate availability becomes.

3. Include Protein and Healthy Fats

Protein provides the building blocks needed for repair and adaptation.

Healthy fats support:

  • Steroid hormone production

  • Cell health

  • Vitamin absorption

  • Overall wellbeing

A balanced diet supports the whole endocrine system.

4. Sleep and Recover

Sleep supports:

  • Growth hormone release

  • Muscle repair

  • Hormone regulation

  • Immune function

Recovery is where training adaptations happen.

5. Balance Training Stress

Training creates the signal for improvement.

Recovery allows your body to respond.

Without enough recovery, the stress load can become too high, increasing the risk of fatigue, injury and hormonal disruption.

The Takeaway

Your hormones are your body's communication system.

  • Steroid hormones help regulate growth, repair and long-term adaptations.

  • Peptide hormones manage fuel, recovery and tissue repair.

  • Amine hormones support exercise responses and metabolism.

The best way to support your hormones is not through shortcuts.

It is through the fundamentals:

Fuel enough. Recover well. Sleep consistently. Train sustainably.

Because your body cannot adapt to training without the energy and recovery to support it.

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