Every month I get the same question: “Do I really need an INSCYD test, or can I just use an FTP test?”
Fair question. INSCYD testing isn’t cheap (199-449 EUR), and if you can get the same results from a free 20-min FTP test, why pay?
The answer: It depends on your goals.
In this article I’ll tell you exactly when INSCYD testing actually makes a difference, and when you can save your money.
If you’re interested in the difference between VLamax and VO2max — the two parameters INSCYD measures — also read VLamax vs VO2max: What Matters More for Endurance?.
What INSCYD Testing Is (and What It Isn’t)
INSCYD is metabolic profiling. It doesn’t just test your power (that’s what an FTP test does) — it tests how your body produces energy.
What I get:
- VLamax (glycolytic capacity)
- VO2max (aerobic capacity)
- FatMax (fat oxidation)
- Anaerobic threshold
- Aerobic threshold
- CHO/Fat consumption at different intensities
What I don’t get:
- Better fitness (the test itself doesn’t do anything)
- Magic numbers that solve everything
- An excuse if you’re not training
When You Don’t Need an INSCYD Test
Let’s be real. Here’s when you don’t need an INSCYD test:
1. You’re a complete beginner (training <6 months)
If you’ve just started structured training, an INSCYD test won’t help you.
Why? Because your physiology is going to change drastically anyway. If you test today, the results will be outdated in 2 months.
Instead:
- Do an FTP test every 4-6 weeks
- Get familiar with TrainingPeaks
- Learn to follow a plan consistently
- After 6-12 months, once you’ve stabilized, do an INSCYD test
2. You don’t train with a plan
INSCYD gives you data. But if you don’t follow a structured training plan, the data is useless.
Imagine you get a report: “Your VLamax is too high for Ironman.”
OK. Now what? If you don’t know how to train to lower VLamax (and if you’re not training consistently), the test is a waste of money.
Instead:
- Start structured training (on your own or with a coach)
- Once you’ve built consistency (3+ months), get tested
3. You don’t train enough hours/week
If you’re training 3-4 hours/week, physiological optimization is not your limiting factor.
Your limiting factor is volume. If you’re only training 3 hours/week, INSCYD won’t tell you anything you don’t already know: “You need more miles.”
Instead:
- Build your volume to 6+ hours/week
- Once you’ve got consistency, that’s when testing makes sense
When an INSCYD Test Actually Makes a Difference
Here’s when testing can change your training — and your results:
1. You’re preparing for a specific event (Ironman, gran fondo, ultra)
If you’re preparing for a long endurance event, INSCYD is a game-changer.
Example: Training for an Ironman vs a sprint triathlon is completely different. It’s not just about volume.
INSCYD tells me:
- Whether your VLamax is too high (poor endurance)
- How to optimize FatMax (crucial for IM)
- What your CHO consumption is at race pace
Result: Instead of generic “train low intensity,” I get exact zones and exact focus (e.g., “lower VLamax by 20%, raise FatMax”).
2. You’re stagnating despite consistent training
If you’ve been training consistently for 6+ months but your results aren’t moving, the problem isn’t motivation or discipline.
The problem is in the training itself.
An INSCYD test shows:
- Whether you’re training the right systems for your goal
- Where your limiters are (VO2max, VLamax, economy)
- What to train to remove the bottleneck
Real-world example: An athlete was training 10+ hours/week, but FTP hadn’t budged in 6 months.
The test showed: VO2max excellent (68), but VLamax too low (0.25). The problem: He couldn’t produce enough power at threshold because he lacked glycolytic capacity.
Solution: 8 weeks of short, intense intervals. FTP +15W.
Without the test? He’d never have known that the problem was too little high-intensity training.
3. You’ve tried “everything” but still have problems
- Training consistently but bonking on long rides?
- FTP is high but you can’t hold power in races?
- Training shows progress but races are a disaster?
These are signs of a metabolic mismatch between your training and your goal.
An INSCYD test answers:
- Why you’re bonking (poor FatMax utilization)
- Why you can’t hold power (VLamax too high for your goal)
- Why races don’t match training (you’re training the wrong systems)
4. You want to optimize your race nutrition strategy
An INSCYD test tells you exactly how much CHO you burn at different intensities.
Example: At 250W you burn 60g CHO/hour. At 280W you burn 85g CHO/hour.
Practical outcome: If you’re riding 280W at an Ironman, you know you need 85g/h of intake. If you only take in 60g/h, you’re going to bonk.
Without the test? You’re guessing. With the test? You know.
5. You’re paying for a coach (or you are a coach)
If you’re paying 100-250 EUR/month for coaching, then a 199 EUR test is a very logical investment.
Why? Because a coach is only as good as the data they have.
If you don’t give them data, they build a plan based on assumptions. If you give them an INSCYD profile, they build a plan based on your actual physiological data.
When to Get Tested
Best practice:
- Start of goal preparation (12-16 weeks out) — Baseline test
- Mid-preparation (6-8 weeks out) — Check progress
- After the goal event/season — Evaluate, plan next season
Don’t test:
- During a build block (waiting for supercompensation)
- When you’re fatigued (test results will be poor)
- Right after illness (wait 2 weeks)
Which INSCYD Package?
I offer 3:
INSCYD Starter (199 EUR):
- PPD test (power-based, no lactate)
- Enough for most recreational athletes
INSCYD Performance (299 EUR):
- LA test (lactate analysis)
- More accurate
- 12-week plan included
INSCYD Complete (449 EUR):
- LA test + MOXY (muscle oxygenation)
- Premium package
- 16-week plan + check-ins
My recommendation:
- First test? — Starter or Performance
- Serious goal (IM, important race)? — Performance
- Maximum optimization? — Complete
Is It Worth It?
It depends.
If you:
- Train 6+ hours/week
- Have a specific goal
- Follow a training plan
- Are stagnating despite the effort
— YES, it’s worth it.
If you:
- Are a beginner
- Train <4 hours/week
- Don’t have a specific goal
- Don’t follow a plan
— NO, save your money. Start with an FTP test and structured training with a coach.
Final Thoughts
INSCYD testing isn’t magic. It won’t make you faster overnight.
But it will precisely tell you:
- Where you are
- What you need to train
- How to reach your goal
For some, it’s a game-changer. For others, it’s too early.
Now you know which group you’re in.
Ready for an INSCYD test? Check out the packages and book your slot.