Is igcse science a lot harder than GCSE science

The top private schools in the country and some of the top state grammar sit IGCSEs because they think they are a better preparation for A levels. If you look at the top performing schools nationally at A level all of them sat IGCSEs, so maybe they have a point. Schools like Westminster and SPGS are not looking for an easy route, they are looking to challenge their pupils.
DS sat a language GCSE after 2.5 term of study and got an A*, he is still fuming about how much easier it is than his proper languages he studied for years at IGCSE.

I think most posters are commenting on the 3 separate Sciences. Have a look at the Edexcel iGCSE Science Double award.
It depends on which GCSE Science was taken if they just have the core Science then there will be more work to cover the rest of the material.
I think the general verdict on iGCSE vs GCSE is that it is easier to obtain a grade C for iGCSE but slightly more difficult to obtain the higher grades i.e. A/A*.

The comment is about igcse generally - but science does have a practical test option (more similar to coursework/controlled assessment or isa that was previously done), the reformed gcse don't have this.

There's no coursework in igcse science user.

The CIE iGCSE science courses that DS1 did last year were much harder than the new AQA GCSE science courses that DS2 is currently studying.

My DD's school (a GS)for some reason did igcse chemistry but aqa for physics and chemistry. I've just taken a look at last years results; there were significantly more A* in the chemistry ( 46%, the highest percentage of the compulsory subjects), but also higher percentages at C or below than there were for the others. So it looks like it isn't (in terms of results) harder for the more able pupils but may be tougher for some.

I'm not sure the comments user made re igcses v gcses necessarily apply to the chemistry- I don't remember DD having any coursework for it at all, and the content seemed good (though rather 'dry') compared to the physics and biology (dh and I have a few chemistry degrees between us so took an interest)

I gcse is considered harder, however all the research shows that they are significantly easier (used by super selective schools, create an elite myth). State schools started to use them and its one of the reasons national results increased. To prevent this erosion of 'standards' they are no longer valid for school performance tables. They certainly aren't harder, in fact you can get a u grade in the examinations, and with coursework still achieve a grade c or even b. This is not something that is now available to state students. Science has many routes (core, additional, extended, separates, synergy, trilogy etc...). You would really need to check the overviews for what is covered, though the general themes are likely the same.

Igcse is considered harder.

It will depend which board they have done and will do. Can you get copies of the syllabus so you can compare what is covered?

DS's (super selective school) does iGCSEs as they consider there to be less of a step up when you move on to A level.