The Three Stages of the Hair Growth Cycle and Why Hormones Disrupt Them

Understanding how your hair actually grows is the first step to understanding why it changes and what you can do about it.

Your hair is always in motion

Most people think of hair as something that simply grows or doesn't. The reality is more interesting and more useful than that. Every single hair on your head is on its own individual cycle, constantly moving through three distinct phases of growth, rest and shedding. At any given moment different hairs are at different stages of that cycle, which is why healthy hair has density and volume rather than growing and falling out all at once.

Understanding these three stages is the key to understanding why hormonal shifts change the way your hair looks and feels and why consistent scalp care matters more than any single product.

Stage One. Anagen. The Growth Phase.

The anagen phase is the active growth phase. This is where the hair follicle is producing new cells, the hair shaft is growing and everything is working as it should. A hair in the anagen phase can stay there for anywhere between two and seven years, which is why some people can grow hair very long while others seem to reach a length plateau more quickly. Genetics largely determines the length of your anagen phase.

At any given time approximately 85 to 90 percent of the hair on your head should be in the anagen phase. When that percentage drops, which is exactly what happens during hormonal disruption, you notice it. Less density, less volume, hair that seems to stop growing at a certain length.

What affects the anagen phase: Estrogen is one of the most important supporters of the anagen phase. It extends the growth period and keeps follicles active and productive. When estrogen drops, during perimenopause, postpartum recovery or other hormonal shifts, the anagen phase shortens. Follicles spend less time growing and move into the next phase earlier than they should.

Stage Two. Catagen. The Transition Phase.

The catagen phase is a brief transitional period lasting approximately two to three weeks. During this phase the hair follicle shrinks, the hair shaft detaches from its blood supply and growth stops. The hair is preparing to shed.

Only about one to three percent of hair is in the catagen phase at any given time. It is a necessary part of the cycle. The follicle is resting and renewing itself before the next growth phase begins.

What affects the catagen phase: Chronic stress and elevated cortisol can accelerate the transition from anagen to catagen, pushing more hairs into this phase earlier than normal. This is one of the reasons significant stress events often show up as increased shedding two to three months later. The hairs that were pushed into catagen prematurely by a stressful period are now completing their cycle and shedding.

Stage Three. Telogen. The Resting and Shedding Phase.

The telogen phase is the resting phase. The hair is no longer growing but it is still attached to the follicle. After approximately three months in telogen the hair sheds naturally. This is the normal daily hair loss of 50 to 100 strands that most people experience without noticing.

After shedding the follicle re-enters the anagen phase and the cycle begins again. In a healthy hair cycle this transition is seamless. The follicle rests briefly then returns to active growth.

What affects the telogen phase: When the body experiences significant hormonal disruption a condition called telogen effluvium can occur. This is where a large number of hairs are pushed into the telogen phase simultaneously, often triggered by childbirth, hormonal changes, illness, crash dieting or severe stress. The result is a dramatic increase in shedding approximately two to three months after the triggering event, which is why postpartum hair loss tends to peak at three to six months after birth rather than immediately.

How hormones disrupt the hair cycle

Hormones are the primary regulators of the hair growth cycle. Estrogen extends the anagen phase, keeping hair in active growth for longer. When estrogen declines the anagen phase shortens and more hairs move into catagen and telogen earlier than they should. The result is increased shedding, reduced density and strands that grow back finer with each cycle.

DHT compounds this by causing follicles to miniaturise over time. As estrogen drops DHT activity increases relative to it. Miniaturised follicles have shorter and shorter anagen phases until eventually they may stop producing hair altogether.

Cortisol disrupts the cycle by pushing hairs into catagen prematurely and depleting the nutrients follicles need to complete a healthy growth phase.

This is why hormonal hair loss is rarely a single event. It is a gradual process driven by the interplay of multiple hormones affecting the cycle at different points.

What supports a healthy hair cycle

The good news is that the hair cycle is responsive. Follicles that have been affected by hormonal disruption can recover when the scalp environment improves and the right support is consistently in place.

Scalp circulation. Blood flow delivers oxygen and nutrients to the follicle. Improving circulation through consistent scalp massage supports the anagen phase by ensuring the follicle has what it needs to produce healthy hair.

Reducing scalp inflammation. Chronic inflammation disrupts the follicle environment and shortens the anagen phase. Anti-inflammatory ingredients calm the scalp and create better conditions for growth.

DHT support. Ingredients like pumpkin seed oil work at the follicle level to support a healthier hormonal environment and reduce the impact of DHT on the growth cycle.

Stress reduction. Anything that lowers cortisol supports the hair cycle. Sleep, movement, scalp massage and deliberate nervous system regulation all contribute.

Consistent nutrition. Iron, zinc, protein and omega-3 fatty acids are the building blocks of healthy hair. Deficiencies in any of these accelerate cycle disruption.

The Sunday Drop approach to the hair cycle

Restore Scalp Elixir was formulated to support the scalp environment where the hair cycle begins. Pumpkin seed oil for DHT support. Rosemary essential oil for scalp circulation. Black seed oil to calm inflammation. Jojoba to regulate the scalp's natural oil balance.

Revival Overnight Hair Treatment supports the hair shaft itself, restoring moisture and strength to strands that have been weakened by a disrupted cycle.

Used together as a weekly ritual they address the hair cycle from two directions. The scalp where growth begins and the strand where the evidence of disruption shows up most visibly.

Your ritual starts at sundaydrop.com.au