What the letters mean
Everyone has two copies of the APOE gene, one from each parent. The gene comes in three common versions: APOE2, APOE3 and APOE4. "3/4" is your pair: one APOE3, one APOE4. You may also see it written E3/E4, e3/e4 or ε3/ε4. All mean the same thing. A 3/4 result is also called "one copy of APOE4," "heterozygous for APOE4" or "APOE4 positive."
APOE3 is the most common version, found in more than half of the general population (MedlinePlus). APOE4 raises the risk of late-onset Alzheimer's disease compared with APOE3, and APOE2 lowers it (Liu, 2013).
What one copy does to the numbers
Genin and colleagues compared 7,351 people with Alzheimer's and 10,132 without, all of European ancestry, against US incidence data. The chance of having developed Alzheimer's by age 85:
| Genotype | Men | Women |
|---|---|---|
| General population (any genotype) | 11 in 100 | 14 in 100 |
| 3/3 (no APOE4) | 8 in 100 | 10 in 100 |
| 3/4 (one copy) | 23 in 100 | 30 in 100 |
| 4/4 (two copies) | 51 in 100 | 60 in 100 |
The authors describe the pattern as semi-dominant: one copy raises risk, and two copies raise it further (Genin, 2011). Risk builds with age, and most of it arrives after 65.
How to read these numbers. They are averages from large studies, mostly of people of European ancestry, so they are not a forecast for you. Other studies give different figures because they count different outcomes (Alzheimer's or any dementia), different ages and different populations. Phoenix explains the differences on its risk by age page.
What it does not mean
- It is not a diagnosis. A 3/4 result says nothing about whether you have Alzheimer's today. Not everyone with Alzheimer's carries APOE4, and many people who carry it never develop the disease (MedlinePlus).
- It does not mean your children will inherit the disease. Each child receives one of your two copies at random, so about half of your children would inherit APOE4 and half APOE3. Inheriting APOE4 raises risk; it does not decide it.
- It does not mean nothing can be done.
What you can act on
The genotype is fixed. The rest is not.
- Lifestyle moves the absolute numbers. In 196,383 UK adults over 60 followed for about 8 years, people with a high genetic risk score who followed a favorable lifestyle developed dementia at 1.13%, against 1.78% with an unfavorable lifestyle (Lourida, 2019). That study used a polygenic risk score, not APOE4 alone.
- Structure helps. In the US POINTER trial of 2,111 older adults at risk, a structured, higher-intensity lifestyle program improved thinking scores more than a self-guided one, and the benefit was consistent in APOE4 carriers and non-carriers (Baker, 2025).
- Measure what you can change. Phoenix tracks 27 APOE4-relevant biomarkers against targets for carriers, such as ApoB under 60 mg/dL and LDL-C under 70 mg/dL, so you see whether what you do moves your own numbers.
How Phoenix helps a 3/4 carrier
Phoenix is built for people who just found out. You bring your result and your questions. You get a personal protocol built around your starting point, your own blood numbers read against APOE4 targets, a daily check-in, and an optional pod: a small group of other carriers matched each month. 750+ APOE4 carriers use it, and 89% see improvement in key APOE4 biomarkers within 3 months. Phoenix earns only from memberships, never from anything it recommends.
Start with the first 7 days guide · Check your blood numbers · Apply to join Phoenix (60-day money-back guarantee)