This article is a translation of the original French article “Épilation Laser: Combien de Séances sont nécessaires pour Éliminer tous les Poils ?” and is intended for the French market. Treatments, availability and prices may differ at our London clinic.
Why Are Several Sessions Needed for Laser Hair Removal?
Laser hair removal works on the principle of selective photothermolysis: the laser's light beam targets the melanin in the hair, generating enough heat to destroy the hair follicle while preserving the surrounding tissue.
However, not all hairs are destroyed in one go. Why? The hair growth cycle has three phases:
- Anagen phase (growth phase): this is when the hair is attached to the follicle and the laser can act effectively.
- Catagen phase (transition phase): the hair begins to detach from the follicle, making the laser ineffective.
- Telogen phase (resting phase): the hair falls out and a new one begins to grow.
Only hairs in the anagen phase can be permanently destroyed, yet they represent only around 15 to 20% of the hairs present on the skin at any given time. This is why several sessions spaced several weeks apart are needed to treat all the hair follicles.
How Many Sessions Are Needed for Each Body Area?
The number of sessions varies depending on the area treated, as some areas are more hormone-dependent than others.
- The face (upper lip, chin, cheeks) requires on average between 8 and 10 sessions, as facial hair is strongly influenced by hormones, which can make regrowth more persistent.
- The underarms generally require between 6 and 8 sessions, as the hair there is dark and thick, making it highly responsive to the laser.
- The legs, where hair is well pigmented and covers a large surface, require 6 to 8 sessions.
- The bikini line is a hormone-dependent area, which explains why 8 to 10 sessions are often needed to achieve lasting results.
- The arms have finer hair, which makes it harder to remove, requiring on average 8 to 10 sessions.
These figures are given as a guide only, as each individual responds differently depending on their skin and hair type.
Factors That Influence the Number of Sessions
Skin and hair type
The contrast between hair colour and skin colour is a key factor in the effectiveness of the treatment.
- Fair skin with dark hair will achieve the best results, as the melanin in the hair effectively absorbs the laser light without risk to the skin.
- Dark or tanned skin requires the use of an Nd:YAG laser (1064 nm), which penetrates more deeply and minimises the risk of depigmentation.
- Fine, light hair contains less melanin, which makes it more difficult to remove.
The technology used: the importance of wavelengths
Not all laser technologies are equally effective.
- The Alexandrite laser (755 nm) is the most effective for fair skin and dark hair. It precisely targets the melanin in the hair and delivers rapid results.
- The Nd:YAG laser (1064 nm) is the preferred option for dark skin, as it penetrates more deeply and reduces the risk of burns or hyperpigmentation.
The Clarity II laser is one of the few devices combining these two wavelengths, making it effective on all skin tones and all hair types, thereby reducing the number of sessions needed.
How Often Should Sessions Take Place?
The spacing of sessions depends on the hair growth cycle and the area treated.
- On the face, sessions should be spaced 4 to 6 weeks apart, as the hair growth cycle is faster there.
- On the body, sessions are generally spaced 6 to 8 weeks apart, as the hair has a slower cycle.
Following the protocol is essential to optimise results and prevent new hair from growing back between sessions.
The Importance of Maintenance Sessions
Laser hair removal eliminates 80 to 90% of hair over the long term, but fine regrowth can sometimes appear under the influence of hormones or ageing.
- Some areas, such as the face or the bikini line, being influenced by hormones, may require one maintenance session a year to maintain results.
- Factors such as hormonal imbalances, pregnancy or age can encourage a few hairs to reappear.
Results to Expect After Each Session
- After the first session, the hairs begin to fall out after 10 to 15 days.
- After 3 to 4 sessions, regrowth slows down and becomes sparser.
- After 6 to 8 sessions, an 80 to 90% reduction in hair growth is observed, with smoother skin and minimal regrowth.
Following the protocol ensures lasting, effective hair removal.
How Can Laser Hair Removal Remove All Hair?
The number of laser hair removal sessions varies depending on the area treated, the skin and hair type, and the technology used.
- Fair skin with dark hair will respond best to the Alexandrite laser.
- Dark skin requires an Nd:YAG laser for effective, safe hair removal.
- A laser combining these two wavelengths, such as the Clarity II, optimises effectiveness and reduces the number of sessions needed.
To obtain a treatment suited to your skin, it is recommended to consult a specialist in order to establish a personalised protocol.
Considering laser hair removal? Book a consultation appointment and discover the best approach for your profile.
